/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraComponent.h
Sets the fixed bounds for an emitter instance, this overrides all other bounds. The box is expected to be in local space not world space. A default uninitialized box will clear the fixed bounds and revert back to emitter fixed / dynamic bounds.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, Category=Niagara) void SetEmitterFixedBounds ( [FName](API\Runtime\Core\UObject\FName) EmitterName, FBox LocalBounds )